🏷️ Basic Information

Make:

Mercedes-Benz

Model:

S-Class

Chassis Code:

W126

Generation:

Second Generation (W126)

Production Years Covered:

1979-1992

Series Designation:

S-Class

Body Styles Covered:

Sedan (W126), Long Wheelbase Sedan (V126)

👋 Introduction

Segment:

Full-size Luxury Sedan

Era Description:

The W126 S-Class represented the pinnacle of automotive engineering and luxury in its time, a benchmark for executive and luxury sedans globally.

Key Competitors:

BMW 7 Series (E23, E32), Audi V8 Quattro, Jaguar XJ, Rolls-Royce Silver Spirit, Cadillac Fleetwood.

Design Philosophy:

Aerodynamic styling, elegant lines, spacious and comfortable interior, advanced safety features for its era.

Manual Value Proposition:

Provides comprehensive factory-level technical data essential for maintaining the complex systems of the W126 series, enabling owners and technicians to perform accurate diagnostics and repairs.

📋 Manual Details

Product Name:

Mercedes Benz W126 Series 1979-1992 Service Repair Workshop Manual PDF

Manual Type:

Factory Service Repair Workshop Manual

Format:

PDF

Language:

English

Delivery Method:

Instant Download

Licensing:

Lifetime Use, No Expiry Dates, No Renewal Fees

Compatibility:

Windows & MAC Computers, Tablets, Smartphones

📖 Manual Coverage

Engine Mechanical:

Engine disassembly, assembly, overhaul, cylinder head, block, crankshaft, pistons, connecting rods, timing components, lubrication system, cooling system (radiator, water pump, thermostat, coolant hoses), seals and gaskets.

Engine Management:

Fuel injection system (Bosch KE-Jetronic, LH-Jetronic, etc.), ignition system (distributor, coils, spark plugs), emission control systems (catalytic converter, EGR), sensors (MAF, O2, throttle position), engine control unit (ECU).

Transmission Manual:

Manual transmission overhaul, clutch system, shift linkage, transmission fluid specifications.

Transmission Automatic:

Automatic transmission (e.g., 722.3, 722.4, 722.5) overhaul, torque converter, hydraulic system, valve body, transmission control unit (TCU), transmission fluid type and capacity, shift solenoids.

Drivetrain:

Driveshaft, universal joints, differential, axles, wheel bearings, rear axle assembly.

Suspension:

Front and rear suspension components (struts, shocks, springs, control arms, ball joints, bushings, sway bars), self-leveling suspension (SLS) system, hydraulic system, accumulators.

Steering:

Power steering system, steering gear, steering column, tie rods, power steering fluid type and capacity.

Brakes:

Brake system components (master cylinder, brake booster, calipers, brake pads, rotors, brake lines), ABS (Anti-lock Braking System) components and troubleshooting, parking brake, brake fluid type and specifications.

Electrical System:

Battery, charging system (alternator, voltage regulator), starting system (starter motor), ignition switch, lighting system (headlights, taillights, interior lights), fuses, relays, wiring diagrams for all circuits.

Climate Control:

Air conditioning (AC) system, heating system, blower motor, HVAC controls, refrigerant types and capacities, troubleshooting AC performance.

Body And Interior:

Body panel removal and installation, doors, hood, trunk, bumpers, glass, window regulators, convertible top (if applicable), seats, dashboard, interior trim panels, headliner, sound deadening.

Chassis And Frame:

Frame construction, rust prevention, jacking points, towing information.

Body Electrical:

Power windows, power locks, power seats, power mirrors, central locking, cruise control, remote keyless entry (if equipped), sunroof operation.

Fuel System:

Fuel tank, fuel pump, fuel filter, fuel lines, fuel pressure regulator, fuel injectors.

Routine Maintenance:

Oil changes, filter replacements (oil, fuel, air), fluid level checks and top-offs, spark plug replacement, belt inspections and replacement.

Troubleshooting:

Systematic diagnostic procedures for engine performance, electrical issues, transmission problems, brake failures, suspension noise, and HVAC malfunctions.

Repair And Rebuild:

Step-by-step instructions for complete disassembly, repair, and reassembly of major components and systems.

Component Replacement:

Detailed instructions for replacing individual parts such as alternators, starters, water pumps, fuel pumps, brake calipers, shock absorbers, etc.

Adjustment Procedures:

Ignition timing adjustment, idle speed adjustment, valve lash adjustment (where applicable), clutch adjustment, brake adjustment.

Diagnostic Codes:

Explanation of diagnostic trouble codes (DTCs) and their meaning, though W126 OBD-I implementation might be basic or proprietary.

Wiring Diagrams:

Comprehensive and clearly labeled wiring diagrams for all electrical circuits within the vehicle.

Depth Of Coverage:

Comprehensive, covering all aspects from basic maintenance to complete engine and transmission rebuilds.

Visual Aids:

Hundreds of detailed photos and exploded diagrams illustrating repair procedures and component identification.

Precision:

Step-by-step instructions ensuring accuracy for professional mechanics and advanced DIY enthusiasts.

📊 Manual Specifications

File Format:

PDF

Print Quality:

High-resolution, suitable for printing individual pages or the entire manual.

Searchability:

Likely text-searchable PDF, allowing quick access to specific topics.

Binding Type:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Families:

M110 (2.8L I6), M116 (3.8L V8), M117 (4.2L, 5.0L V8), M103 (3.0L I6), M104 (3.0L, 3.2L I6 - later models).

280Se/Sel (M110):

Approx. 185 hp @ 5800 rpm, 235 lb-ft @ 4200 rpm (depending on market and injection type).

300Sd/Sdl (Om617 Diesel - Early '80S):

Approx. 114 hp @ 4350 rpm, 170 lb-ft @ 2400 rpm.

300Se/Sel (M103):

Approx. 189 hp @ 5700 rpm, 236 lb-ft @ 4400 rpm.

380Se/Sel (M116):

Approx. 155-160 hp @ 4750 rpm, 205-210 lb-ft @ 2500 rpm (US spec).

420Sel (M117):

Approx. 180-200 hp @ 4750 rpm, 220-240 lb-ft @ 3000 rpm (US spec).

500Se/Sel (M117):

Approx. 230-240 hp @ 4750 rpm, 270-280 lb-ft @ 3000 rpm (US spec).

560Sel (M117):

Approx. 238 hp @ 4750 rpm, 287 lb-ft @ 3250 rpm (US spec).

Fuel Injection Types:

Bosch K-Jetronic (CIS), Bosch KE-Jetronic (CIS-E), Bosch LH-Jetronic (later models).

Fuel Type:

Unleaded gasoline (91 octane or higher recommended for V8s and later I6s).

🔧 Transmission

Transmission Options Early:

4-speed manual (rare), 4-speed automatic (722.3).

Transmission Options Later:

4-speed automatic (722.4 - rare), 5-speed automatic (722.5 with electronic control).

Automatic Transmission Modes:

Comfort (C) and Sport (S) modes on some later models.

📐 Dimensions

Wheelbase Standard:

116.7 inches (2965 mm)

Wheelbase Long:

121.5 inches (3085 mm)

Length:

Approx. 196.3 - 201.4 inches (4985 - 5115 mm) depending on model and body style.

Curb Weight:

Approx. 3,700 - 4,300 lbs (1680 - 1950 kg) depending on engine and equipment.

🛡️ Safety Features

Crash Test Performance:

Designed with advanced safety cage construction for its time. Specific government crash test ratings from the era may vary or not be directly comparable to modern standards.

Anti Lock Brakes:

Standard on most models from the mid-1980s onwards.

Traction Control:

Optional on some higher-end models (ASR).

Airbags:

Driver's airbag introduced as an option in the mid-1980s, becoming standard later in the generation.

Seatbelts:

Three-point inertia-reel seatbelts with pre-tensioners (introduced on front seats later in the generation).

Crumple Zones:

Designed with front and rear crumple zones for energy absorption.

💡 Technology Features

Audio System:

Premium sound systems were available, often with cassette players and early forms of graphic equalizers.

Cruise Control:

Standard or optional on most models.

Automatic Climate Control:

Available on higher trims, offering precise temperature regulation.

Early Features:

While not featuring modern connectivity, early iterations of power amenities and sophisticated climate control set standards for the industry.

🔧 Maintenance

Oil Change Interval:

Typically every 5,000 - 10,000 miles or 12 months, depending on driving conditions and oil type used (consult manual for specifics).

Transmission Fluid Change:

Recommended every 30,000 - 60,000 miles for automatic transmissions (fluid and filter).

Coolant Flush:

Every 2-3 years or 30,000 miles.

Engine Oil Type:

API SG or higher, SAE 10W-40 or 15W-50 depending on climate (consult manual for exact specs and capacities).

Automatic Transmission Fluid:

MB 236.1 spec (e.g., Mobil ATF 220, Castrol ATF Dexron II E) for 722.3/722.4 transmissions. MB 236.6 for 722.5.

Power Steering Fluid:

MB 236.3 spec hydraulic fluid (e.g., Pentosin CHF 11S).

Brake Fluid:

DOT 3 or DOT 4 specification.

Wiring Harness Degradation:

Biodegradable insulation on engine wiring harnesses can degrade over time, leading to electrical issues.

Fuel Accumulator:

Can fail on K-Jetronic systems, causing hard starting when hot.

Heater Monitors:

Can fail, leading to improper HVAC function.

Self Leveling Suspension:

Hydraulic lines and accumulators can leak or fail, requiring specialized service.

Engine Mounts:

Often require replacement due to age and mileage, causing vibrations.

Vacuum Lines:

Cracked or brittle vacuum lines can affect engine performance and accessory functions (e.g., central locking, HVAC flaps).

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and luxury vehicles.

W126 Development:

Developed as the successor to the W116 S-Class, the W126 marked a significant advancement in aerodynamic design and safety features.

Facelift:

Received a significant facelift in 1985, introducing updated styling, improved aerodynamics, more efficient engines (like the M103 and M117 with KE-Jetronic), and enhanced safety features.

Manufacturing Locations:

Primarily manufactured in Germany.

Production Volume:

Over 890,000 units produced globally during its 13-year run, making it one of the most successful S-Class generations.

🏆 Awards & Recognition

Industry Accolades:

The W126 was consistently ranked among the best luxury sedans of its time, lauded for its engineering, comfort, and safety. It was frequently featured in 'Car of the Year' and 'Best Luxury Car' lists from automotive publications.